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A nuclear AAA‐type ATPase (Rix7p) is required for biogenesis and nuclear export of 60S ribosomal subunits
Author(s) -
Gadal Olivier,
Strauß Daniela,
Braspenning Joris,
Hoepfner Dominic,
Petfalski Elisabeth,
Philippsen Peter,
Tollervey David,
Hurt Ed
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.14.3695
Subject(s) - library science , chemistry , computer science
Ribosomal precursor particles are assembled in the nucleolus before export into the cytoplasm. Using a visual assay for nuclear accumulation of 60S subunits, we have isolated several conditional‐lethal strains with defects in ribosomal export ( rix mutants). Here we report the characterization of a mutation in an essential gene, RIX7 , which encodes a novel member of the AAA ATPase superfamily. The rix7‐1 temperature‐sensitive allele carries a point mutation that causes defects in pre‐rRNA processing, biogenesis of 60S ribosomal subunits, and their subsequent export into the cytoplasm. Rix7p, which associates with 60S ribosomal precursor particles, localizes throughout the nucleus in exponentially growing cells, but concentrates in the nucleolus in stationary phase cells. When cells resume growth upon shift to fresh medium, Rix7p–green fluorescent protein exhibits a transient perinuclear location. We propose that a nuclear AAA ATPase is required for restructuring nucleoplasmic 60S pre‐ribosomal particles to make them competent for nuclear export.